Two isothermal challenges yield comparable physiological and subjective responses.

PURPOSE: Ventilated vests are developed to reduce thermal stress by enhancing convective and evaporative cooling from skin tissue underneath the vest. The purpose of this study is to investigate whether thermal stress is equal when a ventilated vest is worn compared to a no-vest situation with similar dry thermal resistance. METHODS: Nine healthy males walked on a treadmill (7 km h-1) for 45 min in a desert climate (34 °C, 20% relative humidity) with and without ventilated vest. Gastrointestinal temperature (Tgi), heart rate (HR), and skin temperature (Tsk) were continuously monitored. Local sweat rate (LSR) was assessed two times on six skin locations. Subjective ratings were assessed every 10 min. RESULTS: Final Tgi (37.6 ± 0.1 °C for vest and 37.6 ± 0.1 °C for no-vest), HR (133 ± 7 bpm and 133 ± 9 bpm) and mean Tsk (34.8 ± 0.7 °C and 34.9 ± 0.6 °C) were not different between conditions (p ≥ 0.163). Scapula skin temperature (Tscapula) under the vest tended to be lower (baseline to final: ΔTscapula = 0.35 ± 0.37 °C) than without vest (ΔTscapula = 0.74 ± 0.62 °C, p = 0.096). LSR at locations outside the vest did not differ with and without vest (p ≥ 0.271). Likewise, subjective responses did not differ between conditions (χ2 ≥ 0.143). CONCLUSIONS: We conclude that two systems with similar dry thermal resistance and, therefore, similar required evaporation, resulted in similar thermal stress during paced walking in a hot-dry environment. Local ventilation did not alter the sweating response on locations outside the vest.

Additional Diagnostic value of Mini Electrodes in an 8-mm Tip in Cavotricuspid Isthmus Ablation.

Background: Eight-mm ablation catheters are widely used in cavotricuspid isthmus ablation (CTI) for treatment of right sided atrial flutter. However a high success rate, these large ablation tips comes with adisadvantage of lower resolution of fractionated signals. Purpose: The aim of this study was to evaluate the additional diagnostic value of the electrograms recordedfrom mini electrodes (MEs) in an 8-mm ablation catheter tip during CTI. Methods: CTI-ablation procedures were compared retrospectively in two groups, namely, group A: the Abbott Safire 8-mm tip with a 3D mapping system (n =37) and group B: the Boston Scientific MiFi IntellaTip XP 8-mm tip without a 3D mapping system (n=13). We analyzedacute procedural success, ablation characteristics and recurrence rate at one-year follow-up. Electrograms from MEs were analyzedright before the onset of the critical ablation application that resulted in acute CTI-block. We determined whether these ME electrograms had additional diagnostic value in addition to of the 8-mm tip derivedelectrogram. Results: At the onset of the critical ablation application, the MEs had an important additional value in 3 out of 13 cases as local signals were sensed on the MEs that were not recorded by the 8-mm tip electrode. In 2cases the ME did not show local electrogramsalthough the ablationwas still effective. Acute procedural and long-term success wereobserved in all patients. No differences were found in time to bidirectional block, procedure time or fluoroscopic exposure. Conclusion: Our data show that signals recorded from the MEs had additional diagnostic value, but only in asmall percentage of the patients. We did not observe, although omitting 3D-mapping in the ME group, any differencebetween groups with regard to procedural or ablation characteristicsduring CTI-ablation.

UVA exposure affects UVB and cis-urocanic acid-induced systemic suppression of immune responses in Listeria monocytogenes-infected Balb/c mice.

Ultraviolet radiation can inhibit immune responses locally as well as systemically. Such effects have been measured in animals and humans exposed to ultraviolet B (wavelength 280-315 nm) (UVB) and ultraviolet A (315-400 nm) (UVA). The precise wavelength dependence is important for the identification of possible molecular targets and for assessments of risk of different artificial UV sources and solar UV. In such analyses, it is commonly assumed that radiation energy from each wavelength contributes to the effect independent of the other wavelengths. Here we show that this assumption does not hold good. In the present study, it was investigated whether exposure to broadband UVA or longwave ultraviolet A 1 (340-400 nm) (UVA 1) prior to the standard immunosuppressive UVB protocol might modulate the immunosuppressive effects induced by UVB. Preexposure to broadband UVA or longwave UVA 1, 1 day prior to the standard immunosuppressive UVB protocol, inhibited the UVB-induced suppression of delayed type hypersensitivity (DTH) to Listeria monocytogenes significantly. This effect was not associated with restoring the number of interleukin (IL-12)-positive cells in the spleen. Since isomerization of trans-urocanic acid (UCA) into the immunosuppressive cis-UCA isomer plays a crucial role in UVB-induced immunomodulation, in a second set of experiments it was investigated whether immunosuppression induced by cis-UCA might also be downregulated by preexposure to UVA. Animals were exposed to broad-band UVA or longwave UVA 1 prior to application of an immunosuppressive dose of cis- or trans-UCA as a control. Both UVA and UVA 1 appear to inhibit the cis-UCA-induced systemic immunosuppression (DTH and IL-12) to L. monocytogenes. These studies clearly show that UVA radiation modulates both UVB and cis-UCA-induced immunomodulation. In general, our studies indicate that both broadband UVA and longwave UVA 1 could induce modulation of UVB and cis-UCA-induced immunomodulation. As sunlight contains both UVA and UVB radiation the balance between these two radiations apparently determines the net immunomodulatory effect.

Natural killer cell activity during UVR-induced skin tumor formation in the Skh hairless mouse.

We analyzed natural killer (NK) cell activity in the hairless albino Skh/HR1 mouse, to study whether the NK cell activity plays a role during UV radiation (UVR)-induced carcinogenesis. In 4 h 51Cr-release assays, spleen lymphocytes of specific pathogen-free (spf) Skh/HR1 mice displayed 5-10% spontaneous NK cell activity. This was comparable to NK cell activity in C57B1/6, C3H and athymic NMRI nu/nu mice, which were also kept under spf conditions. In all strains investigated, the low spontaneous NK cell activity could be increased up to 20-30% by intraperitoneal administration of polyinosinic:polycytidylic acid (polyI:C), a standardized in vivo NK cell induction method. The polyI:C potentiation of NK cells in Skh/HR1 mice was similar to that in C57B1/6 and NMRI, but significantly less than in C3H mice. Chronic daily UV irradiation according to a protocol that was also used for induction of carcinogenesis (11-12 weeks, 95 mJ/cm2 of UV exposure from FS40 sunlamps) did not decrease NK cell activity on a cell for cell basis. Neither was the inducibility of NK spleen cell activity with polyI:C in Skh/HR1 mice during UV exposure reduced. Based on total organ basis, the pooled lymph node cells (axillary, mandibulary and inguinal lymph node) showed a doubling of NK cell activity (P < 0.001), mainly due to an almost 100% increase in the number of lymph node cells. In conclusion, UVR does not suppress the normal or inducible NK cell activity at the time of clinical appearance of skin tumors. This suggests that such suppression of NK cell activity is not likely to contribute to UVR-induced carcinogenesis in the Skh/HR1 strain.

Incidence and management of acoustic neuromas in South Africa.

OBJECTIVES: To determine the extent to which the various treatment modalities are used in the management of acoustic neuromas treated in South Africa and to estimate the incidence of acoustic neuromas in South Africa. METHODS: A telephonic survey was conducted of all otorhinolaryngologists, neurosurgeons, and radiotherapy centers in South Africa to determine whether they had treated any patients with acoustic neuromas during the calendar year 2000. RESULTS: One hundred and fifteen patients with acoustic neuromas were treated in South Africa during the calendar year 2000, and 8 patients were referred to other countries for treatment. This resulted in an incidence of approximately 0.3 per 100,000 population per year. There was a marked difference in the incidence between the various racial groups: the incidence was at least 1.76 per 100,000 population per year among whites and at least 0.01 per 100,000 population per year among blacks. Of the 115 patients, 78 (68%) were treated surgically and 24 (21%) by stereotactic radiotherapy. Fourteen (12%) patients had newly diagnosed acoustic neuromas that were managed conservatively in the year concerned. The surgical approach used was middle fossa in 8 (7%) patients, retrosigmoid in 61 (53%) patients, and translabyrinthine in 9 (8%) patients. CONCLUSIONS: The majority of acoustic neuromas in South Africa were treated surgically, mainly by a retrosigmoid approach. The incidence of acoustic neuromas in South Africa was approximately 0.3 per 100000 population per year. There were significant racial differences in the incidence.

Use and care of an endotracheal/tracheostomy tube cuff--are intensive care unit staff adequately informed?

BACKGROUND: There is an apparent high incidence of tracheal stenosis in the Bloemfontein area. The aim of this study was to determine intensive care unit (ICU) staff knowledge of the use and care of endotracheal and tracheostomy tube cuffs. METHODS: One hundred and twelve qualified nurses, working in 11 different ICUs, were asked to complete an anonymous questionnaire regarding endotracheal/tracheostomy tube cuffs. RESULTS: The results highlight the following three areas of concern: (i) there was an overall misconception in 38% of the respondents that the function of the cuff was to secure the tube in position in the trachea to prevent self-extubation; (ii) accurate regulation of cuff pressure was not routine practice in any of the ICUs; and (iii) only half of the respondents felt their training regarding cuff care management was sufficient. CONCLUSIONS: ICU staff had misconceptions regarding the function and care of endotracheal/tracheostomy tube cuffs. The concept of a higher cuff pressure for better stabilisation of the tube is probably an important factor that could have caused the increase in tracheal stenosis in the Bloemfontein area. Critical care nursing needs to emphasise the use of current techniques, discourage routine cuff deflation, and encourage collaboration with ICU physicians on standards of care. A protocol that could be used in the ICUs regarding the use and care of an endotracheal/tracheostomy tube cuff is proposed.

Salivary levels of immunoglobulin A in triathletes.

We investigated whether the physical exercise of an olympic distance triathlon affected the salivary IgA excretion of triathletes, as a biomarker for mucosal immune defence. 42 triathletes participated in the study. It was found that the salivary flow rate was decreased significantly after the race, thereby resulting in a significant reduction of the total salivary IgA output. The salivary IgA concentration (mg IgA/ml) did not differ, but expressed as total salivary protein, a significant reduction was observed. This was on the account of the salivary protein concentration (mg protein/ml), which was significantly increased. In contrast to the IgA secretion, the salivary amylase activity was increased significantly after the race. Therefore, our data suggest that the exercise of a triathlon may decrease the level of IgA-mediated immune protection at the mucosal surface. As triathletes may during the race be exposed to micro-organisms present in the swimming water, a decreased IgA-mediated immunity during the race may pose triathletes at an increased risk of infections.

Use and care of an endotracheal / tracheostomy tube cuff - are intensive care unit staff adequately informed? : intensive care

Background. There is an apparent high incidence of tracheal stenosis in the Bloemfontein area. The aim of this study was to determine intensive care unit (ICU) staff knowledge of the use and care of endotracheal and tracheostomy tube cuffs. Methods. One hundred and twelve qualified nurses; working in 11 different ICUs; were asked to complete an anonymous questionnaire regarding endotracheal / tracheostomy tube cuffs. Results. The results highlight the following three areas of concern: (i) there was an overall misconception in 38of the respondents that the function of the cuff was to secure the tube in position in the trachea to prevent selfextubation; (ii) accurate regulation of cuff pressure was not routine practice in any of the ICUs; and (iii) only half of the respondents felt their training regarding cuff care management was sufficient. Conclusions. ICU staff had misconceptions regarding the function and care of endotracheal / tracheostomy tube cuffs. The concept of a higher cuff pressure for better stabilisation of the tube is probably an important factor that could have caused the increase in tracheal stenosis in the Bloemfontein area. Critical care nursing needs to emphasise the use of current techniques; discourage routine cuff deflation; and encourage collaboration with ICU physicians on standards of care. A protocol that could be used in the ICUs regarding the use and care of an endotracheal / tracheostomy tube cuff is proposed